What are AD and ED?
For the federal census, each county in each state is divided into enumeration districts (ED); an enumeration district is defined by the National Archives and Records Administration (NARA) as a “basic geographic area of a size that could be covered by a single census taker (enumerator) within one census period.” For election purposes New York is divided into assembly districts (AD) and each assembly district is divided into election districts (ED). Rather than defining new districts for the census, New York decided to use the existing AD/ED partitions and assign one election district to each enumerator (census taker). So a state AD/ED pair is equivalent to a federal ED. Do not confuse the federal term ED with the state term ED — the former is an acronym for enumeration district and the latter for election district.